Have just sandblasted the cylinders and they look all nice and ready for paint. I sprayed water on them to clean off as much glass beads before a thorough cleaning. Put them in the sun for just 20 mins and DAM.. they turned yellow. Here is the pic. You can see the difference cause I scotch brited a small section to show the difference. I'm pissed cause I have to blast them again. Im so surprised they oxidized so bloody quickly. I have a few questions before I start my rebuild project.

1. So must i use compressed air to dry them immediately after using any water ?

2. AND must i immediately after drying off paint them to stop any oxidization?

3. I plan to use Hi-Temp paint. Must I prime with HI Temp paint first.

Its a 1984, its completely stripped down and this is my first project so i hope you dont mind as I will be asking loads of quest along the way. This first post is an immediate prob so the bastards dont further rust.

Edit. Just googled issue. Couldn't find anything for you

RE: Removal of grit after grit-blasting?

Dear All,

As mentioned earlier, gritblasting is first of all used for "activating" (meaning taking off the natural oxide layer of a metal) and secondly for a certain roughness (more surface area). Blast angle and airpressure has to most influence on embedded particles. So, too high air-pressures (depending of the hardness of the surface) and angles between 80 and 100 degrees should be avoided.

After gritblasting a part has to be thermal sprayed within a certain time to avoid the natural oxide layer "growing" back again (Co/Ni alloys within 4 hours, Fe alloys within 2 hours, Ti-alloys within 1 hour, Mg/Al alloys within half an hour).

Indeed a certain contamination by grit particles is almost unavoidable, but does not need to be a problem as long as you meet the tensile bond strength values.

it maybe just super quick to rust again if wet, does seem strange after just 20mins drying in the sun after just been water spray