Ok after I hot coat and start sanding and grinding out, I have a problem where I feel like there is a wax build up on my pad. About literally a minute after I start sanding, the pad won’t even catch traction anymore. The only thing I can think of is that there is too much styrene was added into my hotcoat mixture. If anybody can give me some feedback on what do that would be great thanks.
Howzit tg, I have never seen a hot coat with too much SA in it that would cause the problem you are having and why do you think there is to much styrene in the mix,did you add extra styrene to your resin besides that SA that you added. If your sandpaper is clogging up itmay be not enough SA in the mix and just the opposite of what you think. After you knock the finish off does it sand easier? Aloha,Kokua
oh yea thats the good stuff. the wax did not rise to the surface - could be a couple reasons:
1. not enough (or none at all) surfacing agent (styrene + wax)
2. kicked too quickly and did not have time to settle out after brushing for the wax to rise
3. moisture issues - i have had problems around dusk.
4. tacky resin fairies
usually it is #2
if you can get through the gunk (lower grit paper will help), then you should be able to sand it out fine.
i guess its possible that too much styrene could goof up the works also.....
Thats actually an interesting thought that there isn’t enough styrene as opposed to adding too much. To answer you Kokua, yes. I bought the wax additive and it showed me right on the bottle how much to squirt in per the gallon. So adding more wax additive to the mix will prevent this? Also it sounds too late to even consider it but is there an alternative way where I can sand the boards that had the gumming up pad problem?
And to answer you grasshopper, I tried using a 50 grit paper on my disk today. There was less gumming up going on as opposed to the 80 grit but still it happened and the pad stopped sanding.
Howzit tg, I have to laugh a little since I don't think I have ever seen a can of SA with instructions on dosage but I am sure it was on the can. I have always eye balled the amount by adding a couple of big squirts. As for what to do,Hand sand all the bad resin with 100 grit just enough to take off the sticky part. If there is still enough resin you can use your sander from there on or do another hotcoat over the bad on, but there should be enough resin to finsh with your sander. It's only the surface that is sticky and under is just like a hotcoat should be. I have had this happen twice in 50 years and that was when using UV resin and it kicked before the wax rose to the surface and that is why I use catalyst even with UV resin for hotcoats. To make sure you have enough SA in the resin jut add the SA to it and let it sit a minute or 2 and then look at the resin and if you can see a waxy texture on top of the resin you should have enough and then catalyze and apply to the board. I have to admit that I am better at showing a process instead of writing how to do it so I hope you understand what I am explaining. Aloha,Kokua
Thanks a million Kokua. Yes I understand what you are saying. Im going to lessen the amount of catalyst im using too that might make a difference
I used to follow the suggested percentages meticulously of wax in styrene suggested by manufacturers in my early days and came across your problem...I now just tip it in from the bottle...a splash and then often a bit more for good luck...never had a problem with putting too much in...think I read recently the chemical structure of the resin can break down with too much styrene but my boards seems strong...I've even over egged the amount in the past to thin out the resin for the hotcoat in cold conditions...same effect - boards still nice and strong.
Cheers
Rich
Take the can of SA and set it in a sink filled with warm water. makesure the lid is on. This will heat up the parrafin wax in your SA, and ensure that you will get a hazy, sandable wax layer on top of your hotcoat. Make sure that there are no wax chunks in the mixture. also, kick your hotcoat in about 15 min. Are you using UV cure?
good luck
To astevens, no Im not using UV cure. I actually only use UV cure on the lamination and not the hotcoat. I set the hotcoat off to about 15 cc more or less depending how hot it is.
All of the above. But; You can re-hotcoat correctly and that will do it. Like Kokua said the tacky part is only on the surface. A second hotcoat reacts chemically with the first coat and then it will sand. Make sure your air temp is warm and don't catalyze less. That's why they call it a hotcoat.
I have the same problem when my resin isn’t fully cured yet.
Even something as simple as inadequate stirring can cause the problem. Streaks of non-waxy cured hotcoat will gum up your sandpaper for sure.
Howzit John, So many problems woul never happen if people stirred in the chemicals enough and after any or all chems are mixed in enough then add the catalyst. The only thing this doesn't apply to is when mixing Q-sel into resin, I alway put the catalyst in then the Q-sel .Aloha,Kokua