Spraying Polyester resin

[Franklin]

Has anybody here used a spray gun to spray Polyester resin when laying fiberglass? If so, how did it go? Tips?

 

[48dodge]

Never done it, but I would guess it would work considering gelcoat is polyester resin.

 

[Taylor]

Are you thinking of spraying the resin on top of the dry glass? I can't see how that would work all that well for wetting out.

If you are talking about spraying gelcoat, I have some ideas there.

 

[sailaway78]

Seems to me

That I remember a thread on this some time back. Not real sure, but it sure rings a bell with me. Also seem to remember that there were problems with the gun stopping up. Wish I could remember more. But at least do a search in the archives, and see if you can find it. Not much help I know, but best my feeble mind can come up with.

 

[sailingdog]

The problem is that to spray resin, you have to thin it...

 

[Ross]

Why do you want to do that? there are very good methods that lay on a lot of resin at a time. Tell us more and I can guide you through the steps.

 

[Chris Burti]

Has anybody here used a spray gun to spray Polyester resin when laying fiberglass? If so, how did it go? Tips?

As other have already noted, it is not typically done in production due to the problems associated with combining spray equipment and catalyzed resin along with a lack of any real benefit. My information is seriously dated, but here is what I remember.

Back in the early seventies when I worked for a boat manufacturer, we used chopper guns that catalyzed the resin at the nozzle and combined it there with chopped glass strand to spray lay up into a mold. The irony of the development of this process is that is was developed to permit layup by less skilled workers at a greater speed and lower cost than hand lay-up. However, it turned out that takes a really skilled operator to get a chopper gun lay-up consistently with strength comparable to a skilled hand lay-up.

The biggest problem is that the material itself is so forgiving that you can get a good boat with an average worker, so a lot of manufacturers opted to settle for speed /cost over quality and produced a lot of mediocre (or even bad) boats. and Either way, a crummy job is just that and good one less than common so the process got a bad name.

To spray resin you need a larger cap, orifice and needle for your gun, you need a compressor that can deliverat least 10 cfm at 80 psi constant and you need to retard the resin if you don't want to have it kick in the pot.

I suspect that if I dig around in my shop, I may still have some gel coat accessories and can give the sizes for a Binks gun.