Building my first board and had to go out of town before I could finish, I have the bottom and one layer of the top done, then left town for a month. Do I need to sand the top and around the rails for the lap before I glass my second top layer or can I just clean her up and glass it. I’m using Resin Research epoxy w/Additive F. Thanks for any help,
Just scuff it up a bit with 60 grti and giv eit a wipe down with DNA you’ll be fine.
i remember hearing one of the guys on here say to just scuff with a 3m scotch pad as it does away with the need for dna.
im just about to order a load of 3m vhb tape for work and they sell individual sachets of isopropyl alcohol wipes for cleaning before bonding, woody, is this the same as dna?
dog
IPA (Isopropyl Alcolhol), also known as rubbing alcohol, is different than DNA (Denautured Alcohol) which is ethanol, otherwise known as ethyl alcohol or grain alcohol, with an additive to make it unsafe to drink.
Most hardware stores carry Denatured Alcohol.
Also, I have found that letting RR epoxy cure too long before re-coating results in areas where the new epoxy wont adhere. When applying the fill or gloss coat there will be nickel and dime sized spots where the epoxy pulls away and wont adhere no matter how much you brush it on. What I do with these spots is save a little resin the cup and after coating drop a few heavy drop on that spot and usually it stays. I try to re-coat withing 24 hours and this seems to avoid it completely. I would do more than a light scuff. I would use a sanding pad that will get into the groove of the cloth and sand really well without burning the cloth. Just my 2 cents. There may be others with more experience.
IMO it might be a good idea to wait until Greg Loehr can weigh in on this one.
As far as I know it is best to re-coat epoxy within 48 hours so you get a strong chemical and mechanical bond.
After 48 hours scuff it up really well (without damaging the weave) to get a stronger mechanical bond since the ability for epoxy to chemically bond to itself is weaker after 48 hours of curing time. Wipe with DNA and a clean rag to remove dust and impurities.
Hope this helps
~Brian
I know they say 48 hours, but honestly I start to see adhesion issues after 24. I don’t push it past 24 anymore. It just makes the process much easier to not have those spots where the resin pulls away.
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i remember hearing one of the guys on here say to just scuff with a 3m scotch pad as it does away with the need for dna.im just about to order a load of 3m vhb tape for work and they sell individual sachets of isopropyl alcohol wipes for cleaning before bonding, woody, is this the same as dna?
dog
i was told on this board not to use isopropyl alcohol.
You broke the rules…now you have to go to the School of Hard Knocks…sand it ,wipe it ,do what ever it takes… every thing will work out…
Let me help you with your next board…
Plan a whole day around your epoxy glass job. Temp is very important. 75-80 degrees F and dry is best for me. Get a friend to help. Start in the morning. Lam bottom with 1 layer of 6 oz. take your time , get those laps smooth. wear gloves ,use your fingers if you have to. It takes 2-3 hours for the stuff to cure. Go surfing. When you get back from the beach the board will be ready to flip. Very lightly with 60 grit knock down any bad areas. If you did smooth laps you won’t have any problems. Roll out 2 layers of 6oz and glass the top. Take your time ,get those laps smooth…Go to the local taco stand and have lunch…come home and touch the board with a clean finger. It can’t be wet. If it’s tacky or dry time to hotcoat. No sanding required at this point. After you hot coat the deck crack open a beer. Hang out with your friend and listen to music and talk story…Keep your paintbrush handy and wipe off the drips every ten min…It takes 2-3 hour before you can flip the board so don’t drink too much. Flip board and hot coat bottom!!! Done deal…
Be happy
Ray
rDj - do you wipe the board down with alcohol? whould you say the spots where about the size of a finger print? just a thought.
I see what you are getting at and I doubt it’s my fingerprints. I definitely wipe thoroughly with DNA between coats. Average would probably be about the size of a fingerprint, but some smaller and some much bigger only when it has been more than 24 - 48 hours. They are never near the rails where I would hold the board. They are always towards the center where my hands would be unlikely to touch. Plus I always wear nitrile gloves when handling the board after shaping. I never touch it with bare hands after the DNA wipe down of the blank. So unless I have a little gremlin in the house that likes to touch shiney colorful objects, it’s not oil from fingerprints. It is much more prevalent when I wait more than 24 hours to re-coat. Less than 24 hours and I will maybe get a spot about the size of a pencil eraser if anything.
Thats interesting, I’ve never seen anything like that but I do my glassing within 24 hours also.
Actually I’ve got a board that had to wait to be finned and now needs a gloss, its been sitting around for a couple of weeks, but its getting a PU gloss so it would only be a mechanical bond anyway.
Also I notice the board must have been getting handled alot while my eyes were else where coz there are lots of finger prints (possibly germmlins, more likerly the gromes) so I’ll have to make sure I give it a thorough wipe with DNA.
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I know they say 48 hours, but honestly I start to see adhesion issues after 24. I don’t push it past 24 anymore. It just makes the process much easier to not have those spots where the resin pulls away.
Good point.
No harm in sanding after 24 to make sure it all bonds nicely.
~Brian
Scuff the board up and do your next coat. If you get any small areas that pull away, scrub those with your finger and then brush back over. If you used Additve F in your laminate you will get a good bond with just a light scuff because you won’t have any carbomate on the surface. Add F eliminates that. Alcohol washes are pretty useless after 48 hours so you can skip that. In fact alcohol washes generally are unnessasary if you use Add F. They usually cause more problems then they solve.
Thanks to everyone for their response, got the top layer on and all looks good so far, going to hot coat in the AM and finish her up. Thanks to everyone on the forum for all the info posted, I have used post’s for every step of the build… Thanks again