Galvanising and powder coating

[ajmoore1]

Hi,

I have just finished welding up the frames for my drive way gates. They are constructed out of 80*40mm box section and are going to be clad with oak t&g boards. Each gate is 2m wide by 1.8 high. My plan is to attatch the boards to the frame using m5 stainless steel countersunk bolts top and bottom and with selftappers in the middle. The top and bottom screws will be covered by a cover piece of oak so not visable but the middle ones will be seen. There is approx 20 boards per gate and to be fixed with two bolts top and bottom and one in the middle.

My plan is to get the frames galvanised then possibly powder coated(depending on price!) but i should I drill and tap all the holes prior to galvanising and powder coating or should i do it after. If to do it before I would basically have to clad the gate then dismantle it all. Will the galv/powder coating clog the holes if done first ? If i drill them after coating will they start to rust

any advise gratefully recieved.

Cheers

Jon

 

[s410man]

m5 holes will clog but i would drill beforehand so there is a galv coating there but shouldnt make much difference with a screw in it

dont know if galving is necessary if they are going to be powder coated but as i say i dont know this-just thinking it would be like galving twice

 

[Mikey D]

Ive just done something similar (well i say just still needs fitting after 6 months )

single leaf gate , t and g boards fixed with s/s csk wood screws the boards sit inside an angle frame in my case .
Had it galved , weathered to a nice grey now , the boards will weather grey alllso , i gave my boards several coats of clear preserver , soaking the end grain especially .
The hinge holes just drilled , to be tapped after galving .....

Did think about powder coat on top of galv (after mordant solution wash) but seemed to much hassle plus might get chipped diuring install .

For long life i would powder coat on galv , belt and braces i know ....

i mean not powder coat on bare metal

up to you really ...

cheers mike

 

[Hitch]

For holes that small, id do them after. They dont need to be inline if they are covered... Infact id look at self drillers, theres one for fixing timber to steel.

 

[Welderpaul]

Don't powdercoat onto bare steel if its something thats going to live outside. It won't last 5 mins.

Like Hitch says, i'd use self-drilling tek screws. We recently used some that were stainless, countersunk, and have wings on the tip that drill themselves a clearance hole in the timber, then when they meet the steel, snap off, and drill/tap their own hole. Much easier/quicker.