Bodytube Fiberglassing Question

I have a question regarding fiberglassing bodytubes.

I have been using the basic heat shrink tape method described by Jim Zannuzzo at INFOcentral. Rather than using a roller to apply the epoxy, I use a brush to both apply the epoxy and work on the fiberglass so that it is smooth and clear without an excess of epoxy. I am using West System's 105 resin and 206 slow hardener. I have a "rotisserie" stand that supports the tube with tube couplers that act as a run-off space to support the fiberglass at the end of the tube, as described in Shadow Composites' tape (a great set of videos!). This makes it easy to roll on the fiberglass.

After applying the fiberglass, I wrap a layer of perforated Teflon coated release fabric. Next, the cotton batting goes on to adsorb the excess epoxy. Then a tight wrap of the heat shrink tape, secured to the run-off coupler tubes with masking tape.

Now, rather than putting the whole thing in an oven, as recommended by Jim, I use a hair dryer to shrink the tape (since I'd rather not cure epoxy in the house, and I do not have a curing oven - yet). I make passes lengthwise down the tube, rotating to the opposite sides of the tube for alternate passes, to even the tension on the tube and minimize the chance of wrinkles.

Sometimes, the tube comes out great! - tight, smooth, minimal excess epoxy, requiring minimal sanding. But sometimes I get wrinkles that run longitudinally along the tube. These wrinkles are completely separated from the tube, and when the tube is sanded, the glass cloth is completely sanded through, leaving a gap in an otherwise perfect job.

I suspect the cause is use of the hair dryer, which tensions the heat shrink tape too quickly and un-evenly. My next step is to try to shrink the tape more slowly, taking multiple passes, rather than fully shrinking the tape on the first pass with the hair dryer. The last step is to build an oven. But before I build a curing oven, or heat shrink oven in this case, I am curious what others' experiences have been with this or similar methods.

Thanks, Tom F

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Reply to
fetchen
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Try leaving out the cotton batting and just let the excess epoxy drip off the tube. This bulky layer is the most likely to cause wrinkles, and without it you can see what is going on during the shrink phase. Also, you are less likely to get wrinkles if you only do one layer of glass at a time.

-JT

Reply to
Jeff Taylor

Tom:

It works really well to put on latex gloves and actully spread the epoxy into the fiberglass as your turning the tube. We fiberglass tubes all the time, and method is: Sand tube, spray tack glue, attach fiberglass, apply initial coat of epoxy, roll it and just keep working in the epoxy as needed with latex gloves on. What you apply the epoxy with doesn't matter, since you spread it with the gloves like wringing the fiberglass as it's turned.

We use coated shrink tape

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nothing else. Roll it around the tube with the release side down, heat it a bit with a heat gun to get it started, then toss it in the oven (Shadow Composites Design) at 195 degrees. Tubes come out awsome.

-Boomer

Reply to
Boomer

Any spray adhesive like 3M 77 should be avoided in fiberglass layups. It is not compatible with epoxies, and prevents the resin from soaking into the fibers properly. The result is a weak layup.

While they are a bit more expensive, I've been much happier with Nitril (usually blue or sometimes purple) gloves instead of latex. For small jobs like filleting and building competition models, I reuse the gloves until they tear or get crusty and crack. I just store them in a zip lock filled with baby powder, inside out until next time.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I'll second the Nitril gloves idea big time. I get boxes of them and boxes of awesome syringes from my sis who's a animal vet. Great gloves for creating fillets when used with a little alcohol.

Ted Novak TRA#5512

Reply to
the notorious t-e-d

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Any rocket work is better with alcohol.

RDH8

Reply to
Robert DeHate

I get both at Farm & Fleet.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I buy the Nitril gloves CHEAP at Harbor Freight Tool...www.harborfreight.com

Mark A Palmer TRA 08542...L3

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Reply to
Mark A Palmer

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