UV catalyst for polyester resin

has anyone yet tried this additive to make uv cure resin? 


is it working well? how long must it be exposed to the sun to dry?


As far as I know and i could be wrong… there is only one catalyst for UV on Poly, Its Benzoin ME.

So I am pretty sure that it would be the same stuff as everyone else. just rebranded.

UV is great for learning and needeing to keep the smell down. in full sun it hardens in like 2 minutes.

Cloudy days it will work. it just takes a while

Remember UV light bounces so keep your garage door closed.


We keep a 5 gallon pail of UV around for repairs and fills and such. We keep it in the back of our shop, Yesterday I went to grab some and it kicked from the roll up being open a few days last week. At least 30 feet from the door. and no direct sun…

Storing in Metal is best.

That sounds like the typical UV powder that can be purchased from any supply house here in the US.  Probably just re-packaged.  If you have never used UV follow directions for the amount of powder to be mixed per amount of resin.  Work under artificial light.  No Sunlight; direct or indirect.  No Window shades partially open.  No holes in the ceiling or open doors…  On a lamination you will have lots of time to lay everthing down and tighten it up.  Once your done walk it out into the sunlight and set it on a secure rack for a few minutes. Then flip the board to set the rail.  You’ll be suprised at how fast the process takes pace.  Take it back inside, grind the lap and laminate the other side.  For a hotcoat;  tape of and brush on a nice hotcoat.  Walk it outside and and count to ten or fifteen.  Walk it back inside and set it on the rack.  The resin will start to turn a little cloudy as the wax in the hotcoat reisin starts to rise to the surface.  After ten or fifteen minutes take it back into the sunlight and let it get hard.  Do the other side and you are ready to sand.  A one day board.  No sunlight?? Put it under UV lights.  Polyester resin only.  No Epoxy.  A condensed desription, but should get you going in the right direction.  Lowel

I used some solar on my first build and it takes the fear of pre mature setup away :wink: .  I actually like the stuff and add a little regular catalyst on cooler, less sunny days to keep things moving and allow the board to continue to cure at the end of the day.  I have found the powder works best if it is mixed and then let sit for a while to integrate (out of the light).  The solarez guy uses an old igloo lunch cooler to set his bucket in to keep the light away while he is doing other stuff.  If you are really stretching the resin you can reclaim and reuse unless you put regular cat in the mix.  But the yellow color of the powder gives it away as the same as all others.

…thanks for the detailed information!

sounds good to me.

have a nice day everyone


Occasionally you’ll see a video or picture in a mag. of a glass shop operation.  You may notice that the glassing racks have some kind of make-shift tray or catchment basin under the blank.  Precisely the reason being;  UV resin,  I had a set up for a long time that included a UV box/coffin and catchment trays on the racks.  It’s also nice to have a string of UV lights over one of the glassing racks in the shop.  You can flip that light on and “cure” any UV that winds up on the floor.  I like the idea of using an ice chext to set your UV bucket in until next time.  I used to just throw an old beach towel over mine.  If the resin was clean I would recycle it.  Usually for ding repair.  Several nice things about UV;  You can recycle the resin.  You use less resin,  If you run short you can poor more and keep wetting out.  It is super fast.  It can be catalyzed if necessary.  One day boards.  and it does not require any cure time for a finished board…  It can be surfed immedialtly.  UV Resin — The best kept secret in the industry.  Lowel

Uv cure is awesome. Just a bit of a shame that the boards cme out a bit yellow.

Has anyone used the sunbake additive from shapers? Just wondering if the powder still makes the finished board slightly yellow?


Hey Turtlesurf

I use the UV powder from shapers and it works great. Ive heard that if you mix in too much powder its what makes the board turn a yellow colour. 

Exactly.  I have never had a UV board turn even slightly yellow.  If anything they look clearer and cleaner than Catalyzed Poly or Epoxy. 

Agreed If its yellow its a mixing/ concentration issue.  

…the fact is with UV the resin turns yellower than with MEKP; more noticeable with the new ultra White (polar White) blanks from Surblanks or Arctic, less noticeable with older foam (also from the same brand)

I tested lately and you see the difference.

I guess that with too much powder will be worst, may be that s your case.


-HOWEVER, lately I have been having gassing problems letting the board under the direct Sunlight, that s makes me crazy and turns me on a bad mood, due to I have been found tiny bubbles in places that there were none…so beware with the sun exposure

Don't leave 'em out there in the blazing Southern Hemisphere sun all afternoon while you drink cerveza and pick guitar.  Build yourself a UV box with a timer.

…yes, of course the oven is the way to go here, but unfortunately I have no room to place it (I ll put another question in the forum regarding space and blanks)

but I tell ya that with few minutes and clear board, I found those tiny bubbles…never happened to me before, but I noticed a bit of change in the foam chemistry in the last batch.

I use the liquid form, and have not noiticed any yellow in the finish.

I’m moving to the powder form due to a storage issue (i.e. liquid was going hard / gelling when left and not used) and plan to mix the powder with styrene … then mix into the resin. I got the mix ratio for the crew at Shapers …

Using UV definiately takes the stress out of the lamination. I moved to MEKP for the hotcoat due to weather (i.e. windy conditions, and hence dust & dirt in the hotcoat).

Instead of UV lights, for us backyarderz, I read that you can use a mirror to reflect the light into your shed … mirror on the ground, one on the roof, and even a hand held one to go around the rails.


I have seen those tiny bubbles moving out of the foam too.  Really happens on a warm and very sunny day…  Chaulked it up to the foam and too fast a reaction.  The off gassing of the resin could play a part, but I think it is the foams makeup more to blame.  Didn’t get it with the Arctic foam, but saw alot of it on a reclaimed blank I reshaped and reglassed for a buddy of mine.  Tried a Mellenium foam blank and it seamed good too.

,yes, the foam is the guilty but I put under the Sun due to the UV cat…only few minutes. Never happened to me before with clear boards.

Here there are only few weeks warm and Sunny, then is somewhat cold to very cold and not so Sunny; however, the Sun is very powerful due to the Ozone layer.

Hey guys,

     On the subject of yellow color in the uv, post cure.  I talked to the guys at solarez about that and they confirmed my suspicions.  To eliminate the yellowing, add a hint of blue tint to your resin prior to mixing in the uv cat.  When I say a hint I mean a very small amount.  Very very small.  Silmar 249 b has a bit more blue in it that makes the resin appear clearer and white appear crisp.  I have found this method works quite well and saves me some duckets over the cost of pre mix.

     I also like uv for its speed and even use it in tinted work with a hint of mekp.  Great stuff.  But when you get serious you need to learn to properly use catalyst.  Even with uv you can’t get on without cat.

So do you need styrene monomer with the shapers sun bake or is that just suggested? Would most shapers have this stuff? I’ve been buying my resin locally to avoid freight costs and getting cloth from shapers.

That’s what I’ve been using … Styrene monomer, not to be confused with ‘wax in styrene’ (i.e. which you use to make up filler (hot) coat from laminating resin)

Like others have said in this thread, you can just mix the powder into your resin and save the step of mixing powder and styrene.

I’d be surprised if your resin supplier does not have styrene monomer.

PS: ND, where are you based? Do you know about www.sanded.com.au ?


I’m in bremer bay, WA. So yeah, the nearest is albany, 180ks away. No dramas. Sanded looks cool tho, especially the small bags of resin pigment!!