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I would like to fix up my wood siding before primer and paint. Some areas are chipped, some areas have holes.

Siding2 Siding1

Deciding between outright auto bondo and DAP product

the Bondo suggestion came from one of the home depot reviews on their website against this product, one of the reviewers said it's basically the same product as Bondo, except you get more product with Bondo for less price:

http://www.homedepot.com/p/Minwax-12-oz-High-Performance-Wood-Filler-21600/100376245

DAP product:

http://www.lowes.com/pd/DAP-Plastic-Wood-White-Solvent-Wood-Filler/4013493?cm_mmc=SCE_PLA--Paint--WallRepair-_-4013493:DAP&CAWELAID=&kpid=4013493&CAGPSPN=pla&store_code=102&k_clickID=1c87de18-4c0b-49c7-8c50-ba33a4d3f640

Can someone with experience give me thoughts or suggest a 3rd product?

Thanks ahead

PS -- I hope I'm not breaking any rules by trying to fit in a 2nd question, but please also advise if I should primer and then paint or can just use a paint with primer built in that they sell now-a-days.

  • I usually use a paste of sawdust and wood glue but doing this kind of work I have tons of high quality fine dust to make my paste. I seal with a primer then paint. this would be a 3rd suggestion, I have never tried bondo but have used wood filler also but it is expensive if you have a lot of holes to plug. – Ed Beal Jul 8 '16 at 13:22
  • I have more than holes to plug. There are some pictures below in my reply to Jack. – amalik Jul 8 '16 at 17:41
  • Along the edge of the fence to the wall I would use a latex calk it will last longer than a wood filler especially with temperature swings the filler would start crumbling where the calking would flex. – Ed Beal Jul 8 '16 at 18:58
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I have used all three products. The bondo is the exact same thing as the Miniwax product, with the exception of the color. The cream hardener is the same the smell is the same, the handling properties is exactly the same. The painters in the high end company I used to work for used bondo in the appropriate places. As in not large areas, but for screw holes and perhaps a knot hole but no bigger.

The Dap product is good but you will waste a lot since it dries out incredibly fast. You MUST keep the top on at all times. Keep the lid between the fingers, hinge it back, take a dip of the filler, place it back, and hope you still use it before it dries. It will dry fast on the knife as well, so keep scraping it off as you go or your filling will take a lot of sanding. Personally, I prefer not to use it, although for small projects and availability I have used it recently. Neither the Dap, Miniwax or Bondo is easy to sand.

If all your repairs are small, the bondo will work very well for you. If the repairs are large, say bigger than a quarter, the wood will move and crack around practically any repair you make. With any product you use. You may be able to go a little larger than that, but it depends on the siding and how the wood is cut, as in flat sawn, quarter sawn or rift sawn, but that is another lesson.

7/8/2016 Edit

The picture tells another story, it helped a ton. You do not need filler, except for the knot hole in the second picture. Either product will work there, otherwise the wood needs only to be properly prepped for painting. Resetting the nails that have popped out a bit and maybe filling those with with an exterior grade filler. If they were just set flush and painted over them has been the norm for ages.

The finish is cracked due to the expansion and contraction of the seasonal changes. That is the biggest problem. Getting the surface sound enough to take a latex primer that will give and take with the movement of the siding will be the first step then a latex paint for the finish coats as well. I used to use only oil based primers back in the day, but they are a brittle finish and will crack again just like the finish you have on the siding now. The thing is, no matter what you use, whether it be bondo, or the dap product,or even something as mundane as caulk in the knot hole. make sure the wood is sound and primed before you apply any caulk in any place. Bondo needs bare wood in my opinion to hold, as does the Dap product, If that is used, be sure to prime and paint ASAP.

In my opinion, I would prep the siding for paint, remove all old caulk, prime everything, fill the knot hole with caulk as well as all the joints to the brick, except for the joint at the bottom to the sill ( caulk holds in water as well as hold it out) DO NOT caulk the wood panels together since it looks like you have a board and batten siding detail, and finish paint. Wood needs to move, and it WILL move, caulk will try to hold it in place and cause cracks in the face.

The nails need more attention than I explained at first but it is a matter if the nails that are "proud" are actually holding anything. They either rise off the surface by everything shrinking away from the nail head or the nail point is not in anything substantial and therefore loose and not holding anything. Some of the nails in the siding are overkill, it only take 2 nails in any nailer in the wall to hold siding in place. The third one in the middle gives reason for the siding to split, you are lucky in this case.

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  • Thanks for your input Jack. I know from your Profile on here you've been in the industry since 72, appreciate your input. Let me show you what the wood looks like as well as that may help -- i.stack.imgur.com/TQARX.jpg and i.stack.imgur.com/RFZa7.jpg -- various parts of the house need repairs like that. Your description was very informative, but I still don't know the BEST product to use for the situation. – amalik Jul 8 '16 at 17:40
  • I added more detail to the answer since the pictures revealed a lot. – Jack Jul 9 '16 at 0:00
  • Thanks Jack! I'm not too worried about the nails, I will just hammer them in. If I'm understanding what you said correctly, the hairline cracks can just be primed and painted? Those cracks pictured are the main 'workload', if you will. The 'knot' holes are not as frequent. In that case, it makes my life easier -- Prime and Paint (Latex) for all the hairline cracks, and handle the holes with the mentioned products. When I originated this question, I thought all those hairline cracks need wood filler & then sanding which is a lot of work since more than half of the wood siding has these cracks. – amalik Jul 9 '16 at 8:06
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That's the exact purpose of the DAP filler you linked to. It's stable and safe for use in or outdoors. Primer + Paint is usually sufficient, but if you want to be extra sure, you can (after waiting for the filler to cure) spray some oil-base Kilz primer over it.

At that point, the void is filled and hermetically sealed. If you want to, you can paint a watercolor landscape over it.

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Your answer is in your question. Wood filler is for wood and Bondo is for steel. Although they may have similar ingredients and have the same purpose, both are very different things and will react differently when not used as intended.

The chemical reactions to the products on their intended materials is the key. I am pretty sure that Bondo would fill the cracks with no ill effects and may last and produce desired results. However, because Bondo for cars is made for steel and not wood there is no way to know unless you try it. But then you are gambling. So the next question is what is more important to you, taking a chance on something cheap but unknown, or spending a little more to get the product that was made for your situation.

You also need to know that paint made for a car and for your home also are chemically matched for the materials they are intended. You could probably still get away with painting your Bondo patches with house paint but again, it's a gamble.

As for your second question, you can use either as both are intended to both prime and paint. However, there are usually circumstances where you may want to use one method over the other. Depending on the type of wood you are using, the climate, the exposure to the elements, etc. help me decide if I want to thoroughly prime the bare wood first or if I can get away with an all in one coat. Paint is extremely expensive these days and bad prep work can make even the most expensive paint look bad or not last/protect as it should. Your best bet is to talk with the paint specialist where you are making your purchase and tell them about your particular project. They can help you match the best product(s) for your case. There is usually one person that really knows their stuff. Just hope they are not on break and you get the guy from appliances.

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