MX-5 OC Forum

 Hi,

can anyone recommend person/company to do some sand blasting in our area ?

thanks

 I have a sand blaster, what is it you need to blast?

 I've purchased a cam cover and was told it will need sand blasting before i can get it powder coated,i thought it would only need degreasing but was told by the powder coaters that it would be a better finnish when blasted.

Sand blasting will probably leave a rough "cast" finish. If you want your powder coated cam cover to have a smooth, shiny finish then bead blasting might be preferable.

Many powder coating workshops will have their own blast cleaning facilities (it is an essential preparation stage for many powder coating operations) so try and find one that does.

 I thought there were different grades of blasting or is this not true

5UMO:

 I thought there were different grades of blasting or is this not true

It is indeed true. There are also different types of blasting media. Media such as sand, grit and aluminium oxide tend to be "sharp" and leave a highly textured finish, especially on relatively soft materials such as aluminium alloys. Glass bead blasting leaves a finer finish that forms an ideal surface for priming and powder coating. AFAIK, alloy wheel refurbishers tend to use bead blasting rather than sand/grit blasting.

 So should i be asking them to bead blast it, it's not in bad condition just a bit greasy.

Depends on what type of finish you require and how thick the powder coat finish will be.

If you want a coloured, textured finish then I should imagine that a thorough chemical clean of the casting and then a relatively thin layer of powder coat might suffice.

If you want a smooth finish then it might be possible to hide the original rough cast finish with one or more thicker coats of powder.

Some kind of blasting would probably be a good idea to remove any build up of oxidation on the casting first. I would also imagine that a smoother, blasted surface would be easier to clean and degrease and is more likely to achieve a smooth powder coated finish.

The best bet is to tell the powder coater what kind of finish you require and let them recommend the processes that they would need to perform to achieve the results that you are looking for.

 Hi Niggle

               Thanks for the info it's with the sand blaster today,i will let you know the results once it's been powder coated,

                i'm hoping for a smooth finnish.

5UMO:

Thanks for the info it's with the sand blaster today,i will let you know the results once it's been powder coated,

                i'm hoping for a smooth finnish.

 This will be interesting as the cover is a rough cast finish and I would have thought that to get a good smooth finish, the cam cover should be "sanded" down with wet & dry paper first.  Remember that the final coat of any paint is dependent on the previous preparations.  Will be pleased to read your comments when you get it back and a picture would be nice too.

A few pics of my powder coated cam cover. The powder coater bead blasted the whole cover, as he didn't trust others to do the job properlt [he didn't charge for this, it was in the price]

Also make sure that you remove the thin cover plates on the underside as the heat of the curing process will destroy the sealant. Another thing to bear in mind, if you have an after market oil filler cap you need to make sure that the thread in the top of the cam cover doesn't get coated, I learned that one through experience

Before

After

Showing the plates on the underside

hth---

 Hi Geoff,

               What is the thin cover plates on the underside,and also should i leave the gasket in place so that the paint doesn't cover it,the company doing the coating said that they would tape and cover what was needed but i will check with them what you have said about the oil filler.

What i didn't understand and i did double check with them is that they wanted it blasted, i thought it would just have to be degeased.

I will post some pictures once it's finished.

Geoff did you have the underside of yours cleaned.

5UMO:

     What is the thin cover plates on the underside,and also should i leave the gasket in place so that the paint doesn't cover it,the company doing the coating said that they would tape and cover what was needed but i will check with them what you have said about the oil filler.

The plates form an air duct for the PCV system.

Remove all gaskets and sealant

5UMO:

What i didn't understand and i did double check with them is that they wanted it blasted, i thought it would just have to be degeased.

De greasing is only part of the process, bead blasting ensures an even key for the powder.

5UMO:

Geoff did you have the underside of yours cleaned.

No, just washed it down in a cleaning bath---

 Pictures of  powder coated cam cover, not yet got round to finnishing the lettering, i was thinking of painting them yellow.... what do you think ???

5UMO:

Pictures of  powder coated cam cover, not yet got round to finnishing the lettering, i was thinking of painting them yellow.... what do you think ???

Why not and you could repaint the engine strut bar to match it, colourwise.