haven't written a blog post in a while. Been Very very busy with a huge contract, polishing these 14ft in diameter by 60ft long silos... had to grind down the welds and polish them to a food grade finish. :)
anyways on to the topic... SANDING!!! is definitely the secret to a clear deep shine.
this is one of the top questions i get from customers and certainly one of the most controversial topics in polishing aluminum. most will say, bah no sanding is needed or my truck is in great shape I'll only do a one step sand with a 600 grit... although sanding with only a 600 is possible in maybe 5% of the situations I like to "overkill" and always do an extra step. Often when assessing your job you under estimate the amount of sanding required. there's nothing that sucks more then sanding 600, starting to polish and realizing it wasn't enough and have to start all over again...
so to the nitty gritty... no pun intended :))
TOOLS: you can sand with either a DA sander, or a rotary polisher. DA's are much safer to use, very hard to mess up. The Rotary will save you a TON of time more then half actually... but it's easy to dig valleys and ripples that can show up once you're done polishing, so if you do decide to go the rotary route make 100% sure that you're are always keeping a "flowing" side to side movement, NO STOPING!!!
Let's get started. This tank needs 180 grit to get scratches out, the rest can all be done with 320 as your first step.
My rule of thumb is if I maintain a truck a min of once a year, my grits will be 320, 400, 600 and 1000 then my 2 step polishing process.
Sometimes certain areas will need to be started with a 180 grit. on VERY rare occasions will you need to start with 100/120 grit. These grits are for aluminum that normally hasn't been touched in many many years. and if you do start at lower then 180... make sure your 180 is done very well, the sander marks that 100/120 will leave are brutal if not impossible to remove in the polishing process.
Remember that what ever grit you need/decide to start with is always the bulk of your work, meaning that that grit usually will take you longer then all the other grits put together. so as an example starting with a 180 grit on a rough tank. this step should be done until the aluminum is where you want it to be before polishing, so all scratches and imperfections are gone. This can take anywhere from 15-20 mins to well over an hour or 2 depending on how bad your aluminum is. once this is achieved you move on to the other grits, basically smoothing out the sander marks from the prior grit. once you reach 600/1000 you should start seeing a sheen/reflection in the aluminum. the smoother the surface the better quality clear shine you will get.
Once you get this result, you're ready for polishing.
"The Ultimate Kit" is what I use for all my polishing. 2 steps, 1 cut, one finish and you will get these results. This pic is only after the cutting process using orange/yellow blend airway with 439T Menzerna Green Heavy cut. Still needs to be finished with flannel and 480BLF Menzerna Blue. :)
don't forget, it's always better to sand a little more then not enough.
thanks for reading
Denis Champagne - Master Detailer
DC Super Shine - Owner
Here's a video explaining sanding in depth. Don't forget to subscribe to my channel every little bit helps :) thanks