I find it really hard to know how much time I should spend wetsanding with each grit. Approximately how much time do you spend with each grit when wetsanding a shortboard?
Sand with a grit until you’re done with that grit.
Always have a purpose with what you are doing.
The purpose of sanding with a certain grit is to remove the scratches from the previous grit.
Not trying to be flip, but you need to take as much time as you need, to prepare the surface with each grit. The time will vary, at each stage. I never consider the time, only how the surface is developing.
Bill’s instructions are good. How long it takes is irrelevant. You have to develop the ability to know what you are after. Best to just sand the entire board thoroughly with each grit. But, avoid over sanding and exposing weave. Dial the sander down to slow and low RPM’s. if hand sanding use your hands to “touch and feel” where you are at with each grit. If you wipe a board off with a wet rag it makes it easier to see swirls and scratches. Then you can go to work sanding tose areas. Nothing wrong with using an orbital on the finer grits. Helps reduce swirls. Lowel
I hear you guys, I just find it really hard to see the scratches on a wet surface, especially when working the finer grits. Therefore, I thought a rough estimation of how much time you spend would help a lot. But maybe you´re right and I´ll have to develop a certain feeling for it. The feeling I have right now is: I hate sanding.
Think of it this way, sanding in ALL forms, is the final step in the shaping process. That smoother surface, that sharper release edge, sometimes spell the difference between making a wave, or getting wiped out. Always try to stack the cards in your favor.
When starting out, sanding quite a lot by hand will teach you a hell of a lot. An orbital sander will be your best friend. And as you get more experienced you can use the powersander more and more.
I used to hate sanding, but now I am getting it really wired im starting to quite enjoy it now.
Experience is the main thing that will improve your sanding, that with some good pointers along the way.
thanks for the pep talk, guys. I guess what I find most frustrating is that it is really hard to know where, in the quite long process of sanding, I fucked it up. I use an orbital for sanding it flat, after that only handsanding. Last board I spent 10 hrs of sanding and buffing just to see a lot of scratches in the end. From which grit? Probably one of the early ones, but can´t know for sure
I have a love/hate relationship with sanding. It’s my favorite part of the process to physically see but I don’t really enjoy actually doing it haha
when you say you are sanding and then buffing only to find swirl marks, what is your process?
Are you sanding a hotcoat or gloss? what grit are you starting at? What grits are you going through and in what order?
Are you sanding poly or epoxy?
Haha, I´m totally with you on that. I´m just three boards deep in the game so I don´t really have a process yet, but last time I did a gloss coat and used used dry:240, wet: 320, 400, 800, 1200 (european grit sizes http://www.mibnet.se/home-improvement/sandpaper-grit-size-comparison-between-european-and-us-standards.html ) polishing paste and then boat polish. This was done on RR epoxy with additive F. I´m not after a perfect finish, it´s just that it feels like I have no clue what I´m doing or if I´ve sanded even closely enough with each grit, can´t see any scratches at all when wetsanding.
If you are stepping through the grits in proper order but still see scratches you should wipe after each grit and let it dry in order to find spots that need attention. Putting the board in bright sunlight will help dry it and make scratches easier to see. If working indoors, try a small fan to help dry it quicker between grits.
I will also note that sandng was always my least favorite process…
You have a pretty big jump from 400-800… You probably have left over scratches from the 400. Use some 600 and probably some 1000 as well.
Also, if you are using different paper brands. Pick one and stick with it. Many times one guys 600 is the other guys 800. This is not an absolute but can help cut down on variables.
Depends what finish you need, If you only want a sanded finish I personally only go to 400 Grit, I always use a fresh piece of sandpaper for the final pass, then I give it a quick buff with the wool attatchment with a little spray wax, it just takes away that dull look. Works really well for me- no scratches and clean finish.
Unless you are doing a gloss coat going over 800 is a waste of time IMO
The more you do the better and faster you will get. Some guys start at 220, better glossers start at 400. There is no need to go higher than 600, then to polishes, Perfect-IT black top, and Perfect-It swirl remover ultra blue top on a surfboard that will be surfed is way more than shiney… A wall hanger is another thing. On those I take it down to 1500 grit then the Perfect-It polishes.
When I wet sand I use 3M sponges, they come in fine, extra fine, and super fine. The quality of the paper will dictate if you have to start all over, or move on to the next grit. Cheap paper will give you grief. The rocks will fall off, get stuck in the sander…then come off when you are doing the next grit and swirl the heck out of it. Cheap paper clogs with those resin rocks and swirl mark your fresh board, wobbly unbalanced sander backers will make a mess of your work…Wait for it., wait for it…Buy quality 3M products.
It’s only sanded when its done.
Stupid me,
I always started “Wet sanding” @ 600.
And just
“Rubbed and rubbed till my wrist got numb”
Took a break
And got out the beast and polish.
Much Aloha & stoke!
Hey guys if you haven’t developed the wetsand by “feel” yet,
I have found a really good way to do this is to take a “squeegee” (I use an imitation of the “california blade” and wipe off the water when you think you are done…often times you’ll see otherwise Immediately after wiping as the surface dries in seconds once the water is wiped off. As you get into the higher grits 1000+ It helps to do this in a room with a good light above you. As you get into the higher grits you can see the reflection of the light bulb start to become less hazy as you’re getting there.
Running water is best but in my garage often I’ll just reach for a spray bottle to mist the part. as my hose if frozen for most of the board building season.
This works very well for me, I can paint with a roller and wetsand to mirror glaze. Takes time and patience but using this method you can at least see how it’s going instantly, and not prematurely go to a finer grit when you think you’re ready but actually are not. the end resutl will be shit if you do.
In order to DIRECTLY answer your question I generally won’t wipe to check progress at less than 20 strokes on the same area.
I start with 400,800(sometimes) 1000, 1500 2K then I use meguires ultimate compound + mequires purple cutting pad and compound followed by compound and yellow pad, and polish and yellow pad, All machine polishing done at lowest speed.
I’ve screwed around with a lot of products and am most impressed with the mequires ultimate line up to get the best shine., not disagreeing with the 3M guy….“buy quality 3M products” includes meguires 
(3M bought meguires)
A common rule from car paint shops is no more than 100 between grits when you’re dry sanding and no more than 200 when wet sanding. With this rule you only have to “wipe” the board with each grit, when wet sanding, to cut scratches. Try to use the same pressure. Using high quality sandpaper is the best advice that you got.
All good advice. Especially lemat and resinhead. For a stock glossed board; I used to go through the grits and then straight to # 2 polish. No compound. If you go through the grits properly and don’t leave swirls, there is no need for compound.
Sorry, I can’t help you with the wetsanding question as I rarely do it, but I want to reiterate a couple things that were said earlier.
Use good sandpaper for all phases of sanding, and use the same brand. Personally, I like 3M. Since 3M has different families of abrasives, I try to use products from the same family.
I have a regular paint job that I do which requires lots of fine grit dry-sanding by hand (400 to 600). For this, I absolutely love the 3M Frecut stuff. It holds up great and clogs less than anything I’ve tried. I keep a box of each grit next to my paint booth at all times.
Thank you for your feedback, all good advice. Just one question, this advice to not increase more than 200 when wetsanding, are you talking american grit sizes (CAMI grit) or european standard (ISO/FEPA)? Judging from this link ( http://www.mibnet.se/home-improvement/sandpaper-grit-size-comparison-between-european-and-us-standards.html ), there is a large difference. For instance, my P240, P320, P400, P800, P1200 (european) process seems to translate into something like 230, 280, 330, 450, 650 (if those grit sizes existed in the US). That would also explain why it is so hard for me to find 600 and 800 grit where I live :)
Side note is that iso/fepa graded sandpaper seems to have a smaller range of allowed particle sizes for each grit, which I guess would also be a good thing. However I definitely bought the cheapest stuff I could find, so that could definitely be one of the reasons why most of my sanding goes south.