[LB1972OMC]

Thanks to helpful MTF members (especially Lawnboy77 and Bald-Guy), my D-448 engine is now running and "fully mission capable." It needs only a little carburetor tuning and an rpm adjustment. I hope to restore the deck over the winter and would appreciate advice from those who know this work better than I do.

My self-propelled 1972 vintage 8229B has a cast magnesium deck. Questions:
1. There are several small holes. Do I take it to a welding shop for repairs?
2. Underside has some pitting. Should anything be done other than cleaning and painting? Does the pitting need other repair?
3. Should I try to remove all the remaining old paint before repainting? What is "powder-coating", and is it necessary?
4. Any ideas on removing rust from blade and blade stiffener? Have tried Naval Jelly, muriatic acid, wire brush, steel wool, etc. and have had little success.

This is a "working mower", sees lot of use and will not likely match the fine restorations some of you have done. The restorative work I am doing now, however, is long overdue. I will try to make and post "before" and "after" pictures. Thanks.

Jim

 

[Greenmower]

3. Should I try to remove all the remaining old paint before repainting? What is "powder-coating", and is it necessary?

This is a "working mower", sees lot of use and will not likely match the fine restorations some of you have done. The restorative work I am doing now, however, is long overdue. I will try to make and post "before" and "after" pictures. Thanks.
Jim

Hi Jim,

I can only offer advice on the deck painting aspects of your questions. And, I am not "the expert". I have done two deck restorations and when it comes to the repainting, I would suggest that you sand the entire deck with 320 wet or dry paper, done wet. Just dab the sandpaper in water enough to keep the grit on the sandpaper from clogging up, I have also used SOS pads which are really good for cleaning. Finish with a wet sanding with 400 paper. Then rinse well and dry with dust free cloth. I prime the areas of the deck where I sanded through the orignial paint, prior to putting on the color. Then wet sand with 400 again, rinse, dry and you are ready to paint with color. I would not strip all of the old paint off unless you are going to have it professionally repainted. The factory paint makes a good base coat, is my finding.

I have not powder coated anything, but I would imagine that would be even better. A lot depends on how far you want to go to get it nice, or super nice. I am sure others will respond with their methods for painting.

 

[rhenning]

I do not believe you can weld a magnesium deck. I believe that it will burn if it gets that hot. Togrt

 

[LilysDad]

Don't they sand blast before powdercoating?

 

[Lawnboy77]

Magnesium can be welded, it has to be done with a Heliarc Welder in A.C. mode with pure magnesium rod. I would certainly let a professional do it and whatever you do don't try to use a acetylene torch, a fire and possible explosion can result. I had the deck in my avatar welded with good results, just takes a little time afterwards grinding and sanding down the weld to make it look good, I still left the bead on the underside of the deck though, didn't figure I needed to make the underside look smooth, besides I figured that it helped add strength. If it is just a small hole though I wouldn't have it welded, I would instead just use some JB weld to fill the hole, or holes and then just sand smooth.

I think the most durable coating is going to be powder coat, and probably the most expensive, if you go that route you will probably have to repair the holes afterwards since the heat may melt the JB weld. It might be best to strip the paint yourself with chemical stripper to prevent the media blasting from the powder coat shop from blowing huge holes. I learned this the hard way on my 7022, took the deck into the shop for media blasting and powder coating and got the deck back with extra holes, so I ended up sanding the around the holes, or voids, to get down to bare metal, then I applied the JB weld and let dry for a couple of days in the sun, then I primed and repainted the repaired area with Rustoleum Grabber Green. Turned out really well, you really can't even tell that there was a repair done and I have been using that mower for 2 seasons now.

 

[Lawnboy77]

Here is a before and after pic of the weld repair on my 5234, like I said earlier I wouldn't worry about the pin holes too much, but cracks in areas like what is shown here can cause serious issues later on down the road. At first when I cleaned the deck I thought that this horizonontal crack was just a crack in the paint, but after looking at the underside I could for sure tell that it was cracked all the way through.

 

[Lawnboy77]

Just for info. this deck had the crack weld repair done, then media blasted and powder coated in pale green and then shot with the correct mint green PPG acrylic enamel. The powder coater didn't have the correct mint green color so I went with the closest match for a good base coat so that if the enamel chips it won't be that noticeable.

 

[cityboy]

Lawn-boy 77 is right magnesium can be welded but if the metal is thin it doesn't work trust me. Powder coating is the best way but expensive. So I strip all the paint off because most of the time half the paint is gone any way. Prime and paint and clear coat. If you have money you can have it painted with 2 stage automotive paint but if your like most of us you will be using rattle cans. My avatar was done with rattle cans.

 

[Lawnboy77]

Lawn-boy 77 is right magnesium can be welded but if the metal is thin it doesn't work trust me. Powder coating is the best way but expensive. So I strip all the paint off because most of the time half the paint is gone any way. Prime and paint and clear coat. If you have money you can have it painted with 2 stage automotive paint but if your like most of us you will be using rattle cans. My avatar was done with rattle cans.

I am actually thinking that in the long run it may very well be cheaper with powder coat due to the fact that it will probably outlast the owner because of durability. The way I look at it, I plan on keeping these classics and using most of them and I don't want to have to do another restore in 10 years and I am banking on the powder coating to outlast me. Maybe whoever inherits these machines might have to do another restore, but not me. Don't get me wrong though I am not against rattle can paint, it's a good product, especially for static display, but for day to day use protection of aluminum or mag alloys I just prefer powder coating.

 

[cityboy]

That's true too. Rattle can doesn't seem to hold up very good if you use it regularly. But if your just going to look at it or put it on a shelf and not use it then that might be best.
It's all good.

 

[LB1972OMC]

Thanks, fellas, for the painting tips and advice/warnings on repairing a magnesium deck. I had forgotten about J.B. Weld, but that should be the answer for what I need. I'll try to be patient with the painting, as I know from experience that surface preparation and drying times are critical. Have never used wet sand paper, but may give it a try. If your avatar mower was painted with rattle cans, cityboy, that's nice work and good enough for me (although, my work is not likely to match yours).

Any thoughts on rust removal other than keep at it with what I have been using and be patient?

 

[cityboy]

It all depends on what is rusty. Most of the time you can sand it off or grid it off or sand blast it. Depends!

 

[LB1972OMC]

Presently, I am trying to clean a blade and a blade stiffener. They have plenty of good steel left in them and are worth saving. I don't have sand blasting equipment or other special tools; just a 1/4" drill and hand tools. Sanding has been somewhat successful, but I still have rust in low spots and pitted areas. I guess I will just have to be patient with Naval Jelly and muriatic acid.

 

[cityboy]

A stiff wire brush work wonder to. I have one that I put on my drill to get it down to bare metal. You can wire brush it good and buy a can of that stuff that sprays a chemical that stops rust and then just paint it after it drys.

 

[LB1972OMC]

Sounds like good advice. I'll get on it this weekend and report on how it works, hopefully with pictures!

 

[lawnboy82]

Not to hijack the thread but what is the average price to powder coat a deck? Also I think I recall reading once that you can get a mix of the powder coat that is nearly identical to the original lawn boy color.

 

[Lawnboy77]

Not to hijack the thread but what is the average price to powder coat a deck? Also I think I recall reading once that you can get a mix of the powder coat that is nearly identical to the original lawn boy color.

The coater I use charges 90 bucks to media blast and coat 2 decks and a shroud or 2 thrown in. It's much cheaper to do multiple items at one time. Yes the"Grabber Green" color has a perfect, or near perfect match, it's called "Yellow Green" in the powder coat catalogue that my local coater has. Like I stated earlier, the older mint green color from the 60's doesn't have a match that I am aware of. I will be doing a 1969 beige model next so I guess I will find out if they have a color to match that year.

 

[lawnboy82]

$90 doesn't sound bad, the one deck I stripped with aircraft stripper had to take me at least three hours to strip. I think the powder coat would be the way to go but it makes you wonder if it would increase or decrease your resale value.

 

[Lawnboy77]

I don't know how it would effect resale value, I know personally I would pay more if I knew a mower was powder coated and the color was a good match. I have never really worried about what I was doing to the resale value. I realize that if a person was wanting to make money on these mowers that 100 % restoration is not the way to go. You will easily put way more into it than what you can get out of it. It's a hobby to me and I don't do this stuff to make money anyway.