Your work is designed and cut out, so it’s time to bend it or something right? NOPE. You’ve got to put a finish on there first! Depending on your final finish, you’ll have to go different with strategies at this point.
If you’re going to get the finished product powder coated, chances are you won’t have to go crazy on pre-finishing the material.
But, if you’re a little over the top, you can do a quick random orbital sanding job with the following:
- Pneumatic (or electric) orbital or dual-action sander.
- Various grits of sand paper (80 grit and 100 grit typically will do)
- Deburring tool (if you’ve got a sharp edge you need to take off)
- There are a few options here as well:
- A hand-held deburring tool like one from “Noga”
- Deburring wheel (bench grinder with fibrous soft wheel instead of a grinding stone)
- Dyna-file or some other type of hand held belt sander that is narrow.
- Bench style belt sander
- There are a few options here as well:
Breaking the edge where a burr may be present is important for several reasons, but one of the most important reasons is for safety. I’ve seen people grab hold of material they did not know was sharp plenty of times [and sheet steel can cut DEEP].
If you’re looking to get a plated finish (perhaps you’re working with aluminum and you want a nice anodized finish, or you’re working with stainless steel and you’re looking to get an electro-polished finish, or a zinc-phosphate finish on carbon steel), the finish you put on it now is what you will see forever since plating shows the base layer, unlike paint.
When it comes to aluminum and anodize or alodine (also known as irridite), typically a uniform sanded finish will look GREAT in the final product. But there are a couple of other options as well; potential finish could be a grained finish, which looks absolutely phenomenal if you’re plating any color other than clear.
The same information above applies to carbon steel that is destine for some type of a clear or gold/yellow zinc plating. It’s important to get the finish looking good, because you’re going to see it under the plating (which is kind of translucent) forever.
If you’re looking at electropolished stainless steel, it’s in your best interest to limit the amount of scratches on your work piece! Stainless steel galls very easily and almost any scratches will be clearly visible on your finished product through the plating. Ideally, you’ll want to keep the finish “2B” or as it comes from the supplier of the sheet metal if there are no surface scratches.
Last but not least, you could have a raw finish as well! I’ve found that the best way to achieve this is by knowing what finishes look like. Some people prefer a #3 or #4 grained finish on stainless steel (like some kitchen appliances), since it looks quite good! While certain applications will call for “no finish” or a “random orbital finish”; which can be achieved with either a scotch-brite scuff pad to remove any spatter (if cut by laser), or with an orbital (or dual action) sander that I refernced above.
Once you’ve decided on your finish, you can continue on with your work piece.
Getting the finish laid down before moving on to forming, or welding is one thing that some shops don’t think about. Especially if you’re doing a small run custom part, adding value to your product and providing the best end result for your customer is a top priority!
This is not the last step when it comes to finishing; you’ll have to return the part to the finishing department after it makes a short journey through other areas of your shop (if it requires further processing that is). Unless it’s a flat part, it will need forming and likely some welding/grind work, where the finish will be blended again after grinding.
It’s odd to basically start at the finish, isn’t it?
But, you should be exceptional, and make sure the finish looks the best and most uniform that it can!
The initial finish is just as important as the paint job or quality of powdercoat. 70% of a product’s aesthetic outcome is from “prep work before a finish is applied”.
The Handy Writer 