Shooting straight gelcoat witha 2.5mm tip?

[searaytuna]

I have a 2.5 mm gun for gelcoat spraying. I have sprayed it using acetone & styrene and worked out pretty good. I am sure it prolly degrades its structural properties of gelcoat. Does Duratec pretty much retain all of the structural toughness of gelcoat or should I spray it straight out of the can??

[ondarvr]

You can buy products that are designed to reduce the viscosity of gel coat and help it cure better in a thin film, the place that sold you the gel coat should have them. Duratec will help it spray and level, but you may lose some of the water and weathering resistance if you add too much.

[adamfocht]

Adding acetone to gelcoat kills its physical properties and shouldn't be used as a solution. Duratec clear works wells, styrene in a pinch (but there again it reduces physical properties) What I've found that works best is to warm your gelcoat up. Depending on the type of gelcoat your using, when shooting gelcoat my crew always sprays at 90 - 100 degrees. Your pattern, cover and surface will all be improved and it has virtually no effect on kick times. We generally warm our gelcoat up to 80 degrees using a band heater and static mixing lid, then re-circulate through an inline manifold heater to bring it up to 110 degrees or so, then by the time it flows out of a 50' hose it drops about 10 - 15 degrees.

We spray a variety of tips, our smallest is a 315, 30 degree spray angle, with a 15 thousandths orifice. Considering the MACT compliante gelcoat were using can have high solids in it as big as 12-13 thousandths, this works extremely well. We routinely spray 13-16 mils on high detail areas and usually never run into any problems.

According to the gel coat manufacturer Polygard in Tampa ,Fl. never, ever use acetone to thin the stuff. Use Duratec 904001 at 10-15- or 20%.
According to Greg Burn the Duratec actually improves the physical properties of the gel coat especially in a thin layer. You should reduce your mek by a tenth of a percent or so if using the Duratec.

[ondarvr]

Duratec is a good product for some applications, it helps the gel coat level, flow and spray better, but it will not improve the physical properties of the gel coat.

Well, I think I'll take Greg Burn's word for it since he is the technical rep for Polygard....

[ondarvr]

I'm the technical rep for a much larger resin and gel coat company than Polygard and I have traveled with the owner of the Duratec product line, he's a friend of mine. Duratec products are very good at what they do, but if they made gel coat a better product (water, weather and fade resistant) we would use those same ingredients in gel coat. They fill a small market for specialty products that are used mostly for post coat type applications.

I've been in the marine industry a long time and I'm frequently amused and baffled about how many "correct" but different answers one gets to technical questions depending on who you talk to. Just out of curiosity and to help me trace this down what's your name and company?

[ondarvr]

Doug

Sent you a PM.