Hi guys. I have been using kwik kick epoxy to repair my hyptokrypto board. I filled the ding with q-cell mixture, let it cure then sand it down and laminated. When I laminated I accidentally added to much additive F. Probably 2-3 times the recommended amount. I mix the hardener in by weight, and its hard to get the 2-4% correct when mixing so small amounts. Do I have to sand down the new glass and do it all over again? Im new to this forum, and didn’t know where to post this. Regards from Eirik
you shouldnt be adding additive f to your lam process anyway.
So regardless of how much you put in, you screwed yourself from the start.
You’re probably fine, but your repair might be cloudy or slightly discolored. I’m guessing the repair hardened up just fine. Additive F is mostly an epoxy thinner and leveler. It tends to evaporate off and leave some styrene, which I suppose could cause issues at higher concentrations.
Thanks a lot! I will leave the Additive F out for my next lamination then. The mixture looked cloudy when I poured it yes. But I should still use it for the last coat?
I have a question about sanding the lamination. I used a squeege and tried to make a tight lamination, and you could see the weave pattern without any excess resin floating. I know I should feather out the edges of the cloth. But how much should I sand on top of the lamination? Should I just remove the shiny parts?
You should be fine. Don’t want to contradict a pro glass shop like Acqua but Greg Loehr (owner/inventor of Resin Research) DOES use additive F in his lams in his instructional videos that he did some years back. I always do (1/2 the amount I use on a hot coat). You don’t need to sand the lam at all as long as you are going to hot-coat it soon. And yes, you SHOULD use additive F in the hot coat because it is helps with sanding and prevents fish-eyes.
Thanks for the input! I got home from work, and it was a bit hard to cut away the tape now, so I probably need to sand it off. How soon do I have to put on the hot coat? The same day?
Most new surfboard epoxy resists do not need surfacing agents and then if needed only with last coat. Epoxy resin has three steps, the initial lamination coat. Then the filler coat(second application) that can be applied just past sticky of lam coat. The last coat(third coat) would allow you to sand finish or take to polish. I try to be around to take off tape. Kwick kick should allow you to safely take tape off within 30 minutes without run off. If I can get the board level for the repair I might not even tape off initial lamination. Maybe tape off filler coat(second coat) to make for less sanding if applicable.
Thanks a lot for the thorough explanation. I guess I need to plan the ding-repair a little better and be around. Not so smart to laminate over tape and then go to work;-) I tried to laminate without tape, but the edges of the cloth got a bit messed up by the squeege. But at that time, I didn’t have real surfboard cloth at hand.
If I was you I’d just feather the edges down to the tape. Once the inside tape edges are exposed, pull, then hand sand the whole repair lightly. Once it’s all scuffed, lay down some new tape along the edges of the repair and continue with your fill coat, etc. Pull tape when epoxy is tacky.
Thanks for the tip! Is 60-80 grit ok? Or should I go to 120 when i light sand by hand?
Here is a trick to mixing small quantities. The specified mixing ratio is 2ml per 1 oz of hardener. So that is 2ml F per 30ml or .067 ml of F per ml of Hardener.
So lets say you want to make up a small batch using a 1/8 teaspoon of hardener with 1/4 teaspoon of resin. There are 5ml in a teaspoon so 1/8 tsp= 1.25 ml
Multiply the ml’s of hardener by .067 1.25x.067=.083 ml of F
So that is a pretty small amount but I keep on hand 1ml plastic syringes that I bought on Amazon. It is quite easy to measure out .1 ml in a 1ml syringe. I think .1ml is close enough to .08. If you make bigger batches, the accuracy gets better.
I am not exactly sure where the mixing ratio comes from but this link shows a bottle and the bottle label says 2ml/oz hardener.
https://greenlightsurfsupply.com/products/epoxy-resin-research-additive-f?variant=1052047991
That link also suggest using 1ml per oz of hardener.
Thanks! A syringe with ml-measurements sounds very clever:-)
haven’t used additive F or equivalent surfacing agent in over 10 years. When I did use it I used the cap on the can to measure. The problem with additive F is the solvent evaporates over time and the ratio of wax to solvent becomes more concentrated and can cause problems even with the correct mixing per manufacturers directions. Most quality surfboard resins made today do not need additive F. In 1999 it did.
Thanks bb30! Since I live in Norway I have had troubles finding high quality epoxies for surfboards. First time I did a repair I used the West System epoxy…it has a impracticable mixing ratio, and the repair yellowed fast. Got the kwik kick from seabase in uk, and was amazed by how much better it was to work with. Would be fantastic if its possible to get even better resins. But the shipping is usually a problem. Locally theres only west system, solarez, or other small ding-kits.
I actually think any modern two to one ratio surfboard epoxy does not need surfacing agent. For flow issue of resin, warm resin only in warm water or microwave. when warm to your needs, stir in hardener and consider shorter pot life of mixture with the warmer temps. Never microwave surfacing agent or hardener. I would imagine Norway has a few boating and sailing shops that might carry surfboard supplies or could get what you want with out the shipping problems
I heated the resin in a water-bath, because the whole bottle had solidified during the winter. I also heated the add f since it was solid. And I have googled every boatbuilding company here without finding surfboard resin. But maby some of those resins are suitable, but its hard to understand which chemical properties to seek. For example: none of the resins I found said “uv-stable”. Low exotherm is also good for fin-boxes or deeper dings, if I understand it correctly. 
If you have access to Kwick Kick, you’re getting a good product. Just follow the directions. Additive F might be good for full size fill coats or final coats after sanding but don’t worry too much about ding repairs.
Used RR for years in the late 90’s and early 2000’s with great success before surfacing agent was ever available(100 Plus gallons). It’s an unnecessary crutch. When you go to the boat shop if the epoxy is 2:1 ratio resin to hardener it should get the job done. A few boogers in the final coat can sand out just fine. Placing some drops of resin in volcanos with final coat whilst curing is done all the time with pro polyurethane glassing shops. I also soap and water wash and dry off between filler coat post sand and final coat that most pro glassing shops would not do.
Pic of todays final coat with 3 year old green room blanco resin/west coast fast hardener. not perfect but I still have to finish sand.
Okay, great. They also sell other resin-research products there, and I just went for kwik kick. How far is the leap from dingrepair to building my own surfboard?
looks hard to shape the blanks, but so fun to watch pros do it on youtube.
Looks very smooth bb30! Thanks a lot for the feedback guys:-) I really appreciate it.