hey guys.

we got a rust free bed but the fender needs replacing its for my 85 f150. the bed that is on it, is rusting and beat to hell.

question is. what is better

spot weld or plug weld.

i welded in school and did pretty well with thick metal. but that was years ago.

what would be the best bang for my money.

 

Actually Butt Weld, With a spot or a plug there is the lap between the two. this is where the corrosion starts.
Plug and Spot are a hell of a lot easier, but Butt is the most efficient for longevity.
Did the bottom door skins with a but weld, took a while, but there is no lip to catch crap over the years...

 

ok thanks.

hoping to get it on the truck in th spring or summer

ok here the question

im on a tight budget, so would a 90 amp harbor freight be enough to do the job?

 

I think it depends where the replacement panel is and if it is a factory size panel or a patch.
Take a full bed side replacement panel factory did spot welds but we cant do this so plug weld works.
Patch panel say bottom of door you will not see the "lip" on the so plug weld also.


For the "lip" they make seam sealer to seal the open lip when you have over lapping panels.
Also before welding hit the over lapping panels with weld thru primer.


Between the weld thru primer, seam sealer and body work to seal the out side it should last a long time.
I used weld thru primer and plug welded the panels. I will hit both sides of the "lip" with seal sealer then bed liner floor top & bottom.



As for the welder I would spend a little more for a name brand MIG welder with gas.
Eastwood has their name welders I hear are not bad but also sell name brand but get a welder that can use gas. Welders that can switch between gas & flux core wire are good too.


I have a Lincoln think 135 plus runs on 120 volts both flux core & gas and can do alum with a little change of parts. I tried flux but did not like the out come so use gas all the time.
I bought it to do sheet metal repairs but have used it to weld the rear axle tubes to the center on my drag car. Best money I have spent on a tool.
Dave ----

 

its the whole passenger side bedside.

thanks for the info

 

Being the whole side and I think you can get the full factory type panel it is best to remove the bed from the truck to work on it.
Get a spot weld cutter drill bit, they work great. Drill out all the spot welds and remove the old panel. Clean up the left over spot welds so they are flush and hit it with weld thru primer.
On the new panel punch or drill holes where the factory had the spot welds.
Fit it up and start plug welding away. Clean up the plug welds to look stock and finish as needed.


Eastwood also makes a spray with a hose on the can that sprays out 360*. It is made to coat inside of frames, closed rockers, A pillers, roof side panels or anyplace you want protection from rust. They also make a brush on or can be sprayed rust encapsulator that works good for places you can get to.


Also if you have rust you can use Oxy-Gone to kill it. It is a acid you spray on and turns the rust black when it dries. Thing is you cant weld thru it so best to treat the rust, clean up where you need to weld and spray with weld thru primer. After the panel is welded on use the 360* spray as it will creep into places.


That is just some of what I use to fight rust.
Dave ----

 

well do. thanks for the info. love this forum.

 

X2 on the butt weld, but if you're looking for a welder, I suggest the Eastwood mig 135. I've had mine about 2 years now and love it! It comes with a 3 year warranty and a 60 day return policy. For around 300$ you can't beat it

 

Diesel_Brad has a thread on replacing bedsides using adhesive rather than welding. I'll try to find a link to it when I'm home sometime, or do a search for it. With adhesive you can get a good protective layer of paint on everywhere and not burn through it with a welder. Should be a LOT more resistant to rust.

edit: Found it https://www.ford-trucks.com/forums/1...-bedsides.html

 

A lot of the bodymen around here in NY use adhesive. Which seems to work well.

 

I am old school, glue is for models you build on your kitchen table




Thing I have seen with the glue is you have to buy ($$$) a gun to apply it and tubes and like any tubes if you don't use e full thing it goes bad by the next time you need it.


Last time I checked welding wire does not dry up.
Dave ----

 

And for slightly bigger models, too, such as the Boeing 787 and Airbus A350

Interesting read from the previous post about adhesive repairs. As far as concerns about leftover glue going bad, yep, that is to be expected. Since most of us do so little bodywork, there'd be little reason to keep a stockpile on hand. Just buy it as needed. Most vendors will let you return any unopened tubes.

If interested in learning to weld, I'd be glad to teach you everything I know. We could start around 11 in the morning, and then include a break before lunch. We'd have plenty of time for a matinee after that. Maybe two.

All seriousness aside, I'm a card carrying member of the BWA (Barely Welding Association). I started out making bad-looking bad welds. I've since progressed to good-looking bad welds, so there's progress. Do keep in mind the sheet metal on these trucks is fairly thin, which makes it tricky for us mortals to weld.

When laying out repairs, it's generally best to replicate the location of the factory seams, but not always. For example, I think the inner bed sides are spotwelded to the floor, but that's a lot of work to drill out all those spotwelds, grind the bottom layer flat, and then drill up the top layer to make replacement plug welds. In some cases like this, it may be best to leave the factory spotwelded seam alone (especially if still properly sealed) and make a new butt weld next to it. Not always, but it is something to consider.

In the original post, there was a query about the difference between spot welding and plug welding. It barely got covered, so here's more info. Spot welding is two sheets (without any holes at the weld) clamped together by the tongs of a specialized welding machine. Current flow between the tongs leaves a slightly recessed dimple on both sides. You're limited by the reach of the tongs, so access for the machine can be a problem. I have a portable spot welder and it works great for shop use. I rarely use it for autobody work since it can't reach very far from a panel edge.

Plug welding is far more versatile method for joining overlapping sheets. The bottom layer is flat, no holes. The top layer has a series of holes. Clamp the sheets together and fill the holes with welding bead, making sure to melt into the face of the bottom layer and the edge of the hole in the top layer. The two layers are now joined. A good plug weld will have a slight dome to it, unlike the dimple of a spot weld.