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Poor Man’s Alternative to Vacuum Bagging

Posted By: TheManShed

Poor Man’s Alternative to Vacuum Bagging - 03/24/10 07:24 AM

Poor Man’s Alternative to Vacuum Bagging

I’d like to share a trick I’ve been using. A person would have a hard time to tell the difference in a piece made from this method placed next to a vacuum bagged piece. I’ve been using this method for over 16 months and it works really well. All you need is a roll of 3M masking film, a flexible plastic body putty spreader, and some tape. All of these items can be purchased at any building supply store like Home Depot in the paint department and fairly cheap. A roll of the 3M film will last forever.

Vacuum bagging is great but it takes time to set-up and is costly. First there is the investment in the pump and hardware. Then the process it’s self is costly when you add up the cost of peel ply, bleeder cloth, perf cloth, dumb-dumb or liquid nails, bagging film, and what ever else you may need to make or buy for the job. Not to mention that you usually need about 6 hands. Any one thing that goes wrong and you have a large investment that went to hell in a hand basket.

I had near miss on the last lay-up of a hull half but pulled it out of the fire when I was shorted 5 feet of peel ply from my supplier. I was combining two steps into one and it was important to pull the extra resin and bog out of a wet lay-up. (I had my roll of 3M film it saved the over all lay-up but did not allow me pull out the extra resin.) Every time I look at the result I still get pissed but that is part of the game. I could have lost thousands of dollars and about 6 weeks of work from a simple mistake of a store clerk and I never double-checked before the lay-up so I can only blame myself for trusting that somebody else did their job correctly.

Here is the method as I do it on Divinycell foam in this example ½ inch H-80. I find it best to apply a thin layer of bog on the foam first to prime the foam and assure good adhesion. I mix 105 West System resin with 205 fast hardener and some 407 powder. I make it the consistency of hot maple syrup and apply the bog on the foam with the spreader. Just enough to fill the holes in the foam and make the surface of the foam look wet and glassy. I already have my fiberglass cloth cut in this case I’m working with 200-gram unidirectional carbon. I lay my first layer of carbon on the bog and spread the carbon out getting the wrinkles out and pressing it down with my hands picture below. Then I pour on a fair amount of straight resin and squeegee it in really good with the spreader making sure I wet the cloth out and forcing the resin through the cloth. The picture below will show a really wet lay-up with the resin pooling on top of the cloth after getting worked into the weave. Then I lay my next layer of cloth and work it straight with my hands then lightly with spreader. I add just enough resin to wet it out as I work the resin from the bottom layer up.

Now the magic! I cover the lay-up with the 3M film. Here is the important part the writing must be facing up so you can read it! If you have the writing down it will stick to your work! Keep the film tight to avoid wrinkle and lay it on the top laminate 3M side up. Then take your spreader, I dip it in some resin to lubricate it, and apply pressure on the film with long full strokes working from the middle work the excess resin and air from the laminate to the edges. Keep the spreader level and flat especially on the edged to avoid dry spots and you work the film with the long strokes. It usually only takes one or two strokes to compress the fibers and remove excess resin as long as you did not have a really wet lay-up. I tape the overlapping edges of the 3M film several inches past the piece I’m working on to keep the edges from lifting. As long as you applied the correct side of the film when the resin is dry it lifts right off. Don’t try to remove the film before the resin is dry it will remove the resin with it, but once it is cured - magic! You will have a beautiful lay-up with a smooth, compressed, and air free laminate that will be taken for a vacuum bagged job.

The Man Shed



Description: H-80 foam - bulkheads
Attached picture P1010062.JPG

Description: First Layer of Carbon Wetted
Attached picture P1010059.JPG

Description: 3M film done
Attached picture P1010058.JPG
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 07:33 AM

More...


Description: One down
Attached picture P1010057.JPG

Description: First three bulkheads made
Attached picture P1010061.JPG

Description: Bulkhead tacked in place with fore spare tube
Attached picture P1010065.JPG
Posted By: Jake

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 12:41 PM

Mike,

While I agree that that is certainly a step above a hand layup, I don't believe you're getting all the benefits of vacuum bagging by the same layup. I, however, do feel like it's completely adequate for what you are doing though.

Also note that standard polyethylene plastic (available in rolls at any hardware or common store) work just fine for top layer vacuum film and neither side will stick to a cured laminate. In this regard, there's nothing magic about that 3M plastic (other than the price).

One quickie way I vacuum bag is to take a large piece of lexan and put it on my bench. I tape (using masking tape) a piece of polyethylene plastic to the lexan (to keep the lexan reusable). This bottom sheet can be inside or outside your bag seal. I then layup the part to be vacuumed, run mastic tape (thick sticky tape available for about $7 for a 25' roll) around the perimeter of the part either on the taped plastic or the lexan. With the perforated bleeder ply and bleeder fabric in the layup (on both sides if needed) and a small trail of bleeder ply connecting everything to make a vacuum flow zone, I just place one piece of polyethylene plastic over the layup pressing it to the mastic (leaving some slack to draw up). I also use 1/4" high pressure vinyl tubing (the cheap stuff) to make the vacuum connection...which makes sealing it very easy as it's nearly the same thickness as the mastic tape...it's not like you need to pull much volume so the small tubing works just fine.

Coupled with a pair of electric shears (cuts bleeder fabric like butter!), it really doesn't take much time or materials to vacuum bag smallish flat pieces.

I've also found that vacuum bagging to a rigid surface helps prevent deformation. Old counter tops work great too.

PS - I'm loving the sprit tube!
Posted By: TurboCat

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 02:06 PM

Great write up Mike. Thanks for taking time out to post up the pics and description. I know for fact i wouldnt be as far along on my boat as i am if it wasnt for you taking the time to go over everything step by step.
Posted By: Jake

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 02:50 PM

Mike,

What happened to your website - it looks like it's down (and I'm missing a few updates!).


EDIT: nevermind...it's themanshed.NET not .com. You should put a link in your signature so I don't mess that up again! crazy

Jake
Posted By: Anonymous

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 03:02 PM

and Jake, you should sail slower in case someone behind you blows a tack smile
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 03:25 PM

Hey it's daylight again...been keeping some strange hours lately. My work is not yet ready to sand so here are few more pics. Jake I need to update the website just have had a lot on my plate this month. I’m working on building a new computer this one is getting ready to bite it - but it has been a good ole’ mule for 6 years. I’m going with Windows7 so I’m gathering new drivers and updating my software collection. I’ve had family in town getting out of the cold weather in the Midwest and a visitor to The Man Shed that has great interest in the TMS20. Oh yeah I’m looking for a job also….but this is what has been keeping me busy.


Description: Dry lay-up close view
Attached picture P1010002.JPG

Description: ready to fare out
Attached picture P1010003.JPG
Attached picture P1010004.JPG
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 03:28 PM

Getting ready for Kevlar on the tube to hull and carbon on the bulkhead to hull. The other bulkheads fit better. This one was hard to reach, marked with a sharpie on a long stick, a flashlight. droplight, and binoculars. Looking through 17 feet of black carbon hull at a black carbon bulkhead we missed it a bit and this bulkhead will be hard to reach once the hulls are joined so a little extra work now will save from working through a 4” port hole next week.

Attached picture P1010005.JPG
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 04:03 PM

No problem Turbocat! How are you coming along with the project?
Posted By: Seeker

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 04:19 PM

Looks like a good compromise for your bulkheads Mike...I used the same technique since the 70's for surfboard ding repairs, catamaran hull repairs, sailboard ding repairs......in that case it saves a lot of sanding, mimics the curve of the rail, keeps the cloth repair compressed, all with minimum work...once used it to save a bottom laminate when a free-bagging vaccum bag job on a sailboard bottom went bad. Your bulkheads are a nice application of the concept...

Regards,
Bob
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 04:33 PM

I bagged out a few bulkheads and sucked them too dry. I was using E-glass multi tasking and I was not watching the vacuum that close. I suppose I should be more automated on my vacuum system but I'm just a simple man at times. This method is easy and fast and I made sure I had good bond.

Anyway I'm passing it on for those that want to try it. I like the 3M film it is thin and you can feel the resin and see your work.
Posted By: SurfCityRacing

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 06:15 PM

Thanks for the pics, Mike. There's a huge difference between 'talk' and 'do'. You definitely 'do'! Good on ya!
Posted By: flumpmaster

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 06:32 PM

Originally Posted by Seeker
Looks like a good compromise for your bulkheads Mike...I used the same technique since the 70's for surfboard ding repairs, catamaran hull repairs, sailboard ding repairs......in that case it saves a lot of sanding, mimics the curve of the rail, keeps the cloth repair compressed, all with minimum work...once used it to save a bottom laminate when a free-bagging vaccum bag job on a sailboard bottom went bad. Your bulkheads are a nice application of the concept...


If I understand the application of this technique to a hull repair you would:

  • Wet the prepared repair area with resin
  • Apply the cloth, smooth out
  • Apply second and successive layers of cloth - smoothing out between each and just wetting out enought so that cloth is wetted with excess resin from below plus some fresh resin from above
  • Cover with polyethylene film (not saran wrap thickness, but not super thick
  • Squeedgee out excess resin with a spreader through the film (where does this excess go?)
  • After curing, peel off the film and begin fairing


The objective being a drier layup which is stronger and less wrinkly - hence requiring less fairing?

As most of us are more likely to be repairing a hull than building new ones, it would be useful to understand how to apply this to a hull repair. Useful comments from Mike, Bob, Jake and others welcome.

I'm OK at fixing small nicks and dings and the odd split I-20 hull after Lee has been busy in the surf - but I'm self taught and have much to learn

Chris.
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 07:10 PM

Move the excess resin to the edge past the film then you can wipe it clean with a rag when it is wet. In the 5th pic on the post I have an old rag to wipe up "run over". Very little faring is needed. On repair work make sure the patch area is sanded / skuffed to hold the patch and most of all of clean of wax ect….

Object is a drier lay-up, compressed layers of cloth, and getting the air out. Side benefit it is pretty fare to your surface.

Thanks Jeremy maybe I have some of that old Navy SeeBee "Can Do" left in these old bones.
Posted By: TurboCat

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 09:47 PM

Originally Posted by TheManShed
No problem Turbocat! How are you coming along with the project?


Its been a slow go lately because of a rental house im remodeling. The deck is on one hull and an hour or two sanding and the other side will be complete. Im picking up some spare hulls tomorrow that i plan on rebuilding as well. I think on the new set im going to go all out and try some serious bracing to see if i can stiffen up the hulls and possibly run inter20 type beams. The TMS20 is looking great man! I appreciate all your help. I need to send you some cold beer's for all the time ive taken calling you asking dumb questions!
Posted By: Seeker

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 10:31 PM

1) Clean the immediate and surrounding area with Acetone solvent.
2) Roughen the surface with 80 grit sandpaper only where it will be repaired
3) Mask off with plastic all around the repair area, don’t be stingy....a little more plastic and masking tape here can save a lot of clean up later.
4) Precut multiple layers of appropriate cloth (two 4 oz pieces for surfboards) one piece with about a ½” margin larger than the hole, second layer 1” larger than the hole.
5) Fill any deep indention with foam of same type, or skim with resin and glass bubble paste if indention is 3/16” or less deep.
6) With the ding filled with either foam sanded to shape, or Resin/Glass bubbles (while still wet), put a thin coat of resin on the repair area.
7) Wet out both pieces of 4 oz cloth patches on a separate flat surface covered in plastic.
8) Remove the cloth patches from wet-out table and position over the ding, using the smaller one first and covering that one with the larger.
9) Cover the complete area of the repair with plastic sheeting….can even be saran wrap.
10) Take a large auto body plastic squeegee and work all excess resin out of the cloth and onto the adjoining plastic masking….when everything looks optimum spider out from the edges of the top covering sheet of plastic with masking tape to stretch it out smooth without wrinkles.
11) When it has fully cured the plastic will pull right off and you will have a perfectly smooth surface that conforms to whatever compound curves exist.
12) The excess resin will have been pulled onto the adjoining plastic away from the repair area. I like to use the blue masking tape and take a Dual action sander starting with 120 grit paper to feather the exact edge of the repair…the masking blue masking tape is easy to see, and makes knowing just how far to take it down a no brainer.
13) After you have feathered it down on all sides pull up the perimeter masking which takes with it all excess resin.
14) At this time you can lightly sand it and put on a gloss coat…or gel coat if it’s a cat.
A catamaran repair is no different other than using more layers of 4 oz or 6 oz cloth, increasing the overlap of the repair slightly, and adding a coat of gelcoat. I did the bow of a friend’s Hobie 20 several years ago and by using the factory matched gelcoat you could not tell which hull had been damaged in a collision and which hull was untouched.
When everything is listed like this it sounds like a big production…but it really is “stupid simple” and gives a much stronger and cleaner repair. It also avoids damage to the surrounding laminate that often occurs as people try to sand down a high profile lump of resin and cloth.
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 10:44 PM

Hey Turbocat asking questions is better then learning by error. I’ve done my share of both! It’s when you don’t learn by error and nobody to ask that really sucks!

As Mr. T would say, “I pity the poor sucker that tacks in front of me” I would not want to scratch my boat or anything - not one of those guys it’s not worth it. Do T-Bone crashes still happen because nobody gives even if they are right or wrong the ultimate game of waterway chicken at the start line?

The Kevlar isn’t pretty but usually armor plating is ugly and it will be hidden. Now the bow will tear off before the tube breaks, well that was the idea sort of ...Once it is closed a hole would have to be cut in the boat to get to it.

It may look like I have my laminate backwards but my goal was to reinforce the hull skin to the sprit pole case, think about it....?

Later



Description: She ain't pretty but it will work.
Attached picture P1010009.JPG
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/24/10 10:50 PM

Bob great job! reminds me why I stopped offering to do repair work, People never seem to want to pay for all the labor it takes to make the job look great...and grinding glass is no walk in Vero Beach!

Ha!

Mike
Posted By: DennisMe

Re: Poor Man’s Alternative to Vacuum Bagging - 03/25/10 07:40 AM

"She ain't pretty "
What are you nuts? That looks absolutely gorgeous!
Well it does to me...
Posted By: Jake

Re: Poor Man’s Alternative to Vacuum Bagging - 03/25/10 11:37 AM

Originally Posted by DennisMe
"She ain't pretty "
What are you nuts? That looks absolutely gorgeous!
Well it does to me...


I concur!
Posted By: TurboCat

Re: Poor Man’s Alternative to Vacuum Bagging - 03/25/10 01:28 PM

If i run out of acetone while cleaning a repair area can i use MEK instead with no ill side effects?
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/25/10 02:41 PM

You can use Lacquer thinner - alcohol as long as what you are using will not lift your painted surface. Acetone is the industry thinner / cleaner for resins. As long as there not any wax and the area has been cleaned sanding also works.
Posted By: TheManShed

Re: Poor Man’s Alternative to Vacuum Bagging - 03/25/10 02:44 PM

Thanks guys! Nuts well you got to be to do this.
Posted By: arbo06

Re: Poor Man’s Alternative to Vacuum Bagging - 03/26/10 02:52 AM

i know that song, "She ain't pretty, she's my brother!"
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