Making fiberglass stick

[CSX]

I have read about a few people that have used a spray glue, like 3M 77 to make fiberglass stay in place before applying a resin.

I would imagine this must have some adverse side effect with the resin, but would make things much easier in tight spots and sharp bends with hand layup.

Is this a bad idea?

Has anyone tried this or another method?

[Homefront]

I would not do it.
I don't want anything to get in the way of the epoxy penetrating the fabric or bonding with the substrate.
Masking tape, thumb tacks, fishing weights, a helper... all are better alternatives.

Which resin, poly or Epoxy? Overhead surface or what? Newbuild or restoration?

Regards
Richard

[ondarvr]

Like the Apex asked, those answers are needed.


There are tackifiers that do not create flow or bonding issues for each type of resin, they're normally used for closed molding but can be used in hand layup also.

I must say tough, that in 40+ years in composites I haven't needed to use anything more than the resin itself to hold glass in place when hand laminating.

[tinhorn]

I've never tried this because it seems like a really bad idea. I don't have 40 years in the biz, but I have maybe 15 and I've never had this problem either.

If you have some troublesome bends and tight spots, work with them separately. Tear your mat instead of cutting it and the edges practically disappear. You'll have to overlap your cloth, of course.

One of the biggest problems newbies have is putting too much resin onto the fiberglass--THIS will make things slide around A LOT. You'd be amazed how little resin it takes to wet out your 'glass sufficiently. Mix up a small batch of resin and paint it onto some mat with a chip brush. Just stare at it for about 30 seconds and observe how it soaks in. I paint just enough resin onto the 'glass (or onto the mold) so it sticks, then roll it, then go back with my chip brush to paint resin onto the dry areas.

ALWAYS use a nylon or aluminum fiberglass roller to 1) work out the air bubbles, and 2) spread the resin around evenly. (Gelled or hardened resin is easier to clean off nylon than aluminum.) If you see resin puddles or drips, you've used way too much. You can use a regular paint roller to mop it up--in fact, using a paint roller as a final step makes a very impressive finish. (Handle it carefully, though, so as not to raise the 'glass and create huge bubbles.)

Well, on overhead surfaces the amateur is perfectly overcharged and will require some staples or a thick putty to assist.



But in general I concur with you ondarvr and tinhorn.

Regards
Richard

[Herman]

Although not much used when wet laminating (a thickened resin is used more often) it indeed can work. There is not so much difference between hand laminating and resin infusion for that matter.

I sell 3 kinds of spray glue for that application:

-hotmelt. No fumes, but you need a hotmelt gun, and drag a power line and air supply with you.
-Airtech Airtac 2. Good glue.
-Ce-Sense Resin Infusion Spray Glue. Good glue.

For the latter I had a university test the effects of the glue on resin, and shear strength. The outcomes was that effects, if any, were within the tolerances of the measuring method. From the test results one could not determine which panel had glue used, and which panel was "virgin".

If anyone wants the test report, feel free to mail me at hbrouwerjr at brandscomposiet dot nl


Still:
If you do not need glue, do not use it. If you need to use it, use as little as possible. Wetting your surface usually is enough to make things stick.

[ondarvr]

When used correctly the glue type products can work OK, the problem is you're trusting someone to not over use the product. Some people like to put on little more than is needed, or can make a mistake, this leads to weak spots in the laminate and/or a poor surface profile. In some cases I've seen gel coat not bonded to the resin due to the non dissolving glue creating a barrier between the two.

The reactive type tackifiers break down quickly when in contact with resin and don't block the flow during infusion. We've done testing on the effects also and if the glue based products are overused even a little, the physical properties drop. When the reactive tackifiers are used there is no reduction.

Anyone coming from the aerospace closed molding world will know that using a glue based product is not acceptable and can be grounds for termination.

[Herman]

Indeed, you will need to trust your workers for not over applying glue. I guess this comes in the weekly or monthly training schedules that of course every company installed (in a more or less official manner).