Spraying back of parts

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#1

All of my parts are handlaid, and I have a customer who is wanting the back side of his parts sprayed black. What would be the best way to do this and keep cost down?

I thought of 3 ways, just enamal paint after its cured, but that would mean leaving it in the mold longer and taking more mold time. The other way was black gelcoat but that would mean the same thing as above I think. And the last was pigmenting the resin black.

Are their any other options out there, that would possibly not slow me down on demolding?

#2

Black pigment would be the easiest if the customer is happy with the results. rattle can flat black works nice. You could also buy fiberglass that is dyed black and put on as last layer.

#3

What about a Black Diolen fabric in a twill or plain weave. You may be able to swap out one or two of your layers and put down a Diolen in its place so no extra work or mould time required.

"Diolen Polyester Fibre is a low density (1.3g/cm3), high tenacity fibre which has good impact characteristics due to it’s very high elongation and break, however, the young modulus is very low. It is used in applications where high stiffness is not a requirement, but where low weight, high impact resistance and high abrasion resistance is important.

Diolen is commonly used in the manufacture of Canoes and Kayak’s and many more applications where high impact strength is important.
Diolen is best sandwiched between layars of CSM for maximum strength, or effectively laid on the reverse of a laminate, which is usually apparent in canoe/kayak construction."

With a Resin: Diolen ratio of 1:1 , i.e 1 sq mt of 200g Diolen will use 200g of Resin

#4

We usually paint a few parts at a time with a single stage black paint. It works well :). We infuse though so the finish is much nicer.

#5

I am still missing if the part is polyester or epoxy.

#6

I prefer the black fabric as the best solution of all, best in looks. However you can use a brush to paint them with black latex paint and third comes the black pigment in the resin (which usually the back side isn’t that much black after vaccum/ infusion)

#7

They are handlaid polyester. The back side finish is not important on these parts, usually we don’t do anything to them. I just have a new customer that is wanting his parts all black on the back side. I may just have to use a spray can and paint the back side before we trim. I was just curious if there was a better way. The parts are only 1 layer of 2 oz mat, with some reinforcement so changing the layers to a black fabric isn’t really an option.