I've built several back-gouging tools for my own use and will remark on what I see in the photographs and how those features compare with my past experience. I have no interest in testing this tool for several reasons that I hope to make clear below in detail.
First, the tool's base is very wide- like a skill saw where sheet materials are the sole focus. I weld hull seams in three general classes- none of those major classes would allow this tool base to access the places where I need to back gouge. A) at the chine two sheets/plates of metal are at varying degree to one another- from about 90deg to 120 deg (viewed in Section Plan) so the tool's base would not allow the inside of this set of plates to be effectively gouged. B) frames or longs to hull plates- inside the hull. Almost all the welded aluminum elements of a marine structure are at nearly right angles to one another- and that requires a bevel/weld allowance at the intersection of these materials- again the table looks like it would stop blade edge access to these weld allowance cut outs. C) sometimes the hull has external extrusions welded to the bottom or topsides and this set of weld cut outs or weld recesses are like B) above. However in this case, depending on the blade reach and the extrusion cross section it does seem possible this tool could cut these weld recesses? However, I plan them and cut them with a sander/grinder/router before they're assemble so again, the tools' use, for me, is somewhat limited.
Also to note about interior framing welds' prep by back-gouging; the long table stops the blade several inches short of any seam prep at 90 deg to a frame or long's intersection with the hull- so a builder is back to the normally used die grinder with the carbide burr ball or cone to reach up close to the frame member where is crosses the hull seam that this tool might back-gouge.
(D) Hull butt seams; where plate/sheet material is welded at right angles to the keel plane to accomodate short stock on longer boats often requires back gouging once one side is welded. If the inside were welded first, I'll assume a weld bevel or gouge was already on the material edges for this part of the remarks- then the outer hull surfaces would be essentially open; in this one location of butt seams welded insider first (not all builders weld in this sequence) THEN this tool looks like its wide, long, table with the wide inserts would be a potential application for the current design to back gouge that outside seam.
Next is my experience with the blade design. I've purchased hundreds of blades for skill saws, (& some grinders), and plural dozens of custom made carbide insert blades, in the last four decades, to cut aluminum; and the features I see in this design appear to me as potentially difficult to control- safely?
The blade shown has large teeth, but they are gapped by a large gore in front of each tooth- this allows the user (intentionally or accidentally) to advance the cutter's forward progress sufficient to 'fill the tooth face'- that is; the large gore in front of each tooth has in my experience been a very detrimental design feature because the large gore does NOT limit the 'bite'
of any given carbide inserts' engagement. By allowing a nearly unlimited engagement of the insert/blade face- the tool can be 'overloaded' and either stop or slow the tool's RPM. Further on this same vein, the large face engagement can allow this type of blade to dig in and lurch- or kick back!
Having seen the kick-back and control issues with a single carbide insert as the cutting tool's blade, I've adopted this back-gouging method shown below.
By using three blades stacked so the cutting inserts are very closely spaced the tool's edge cannot engage more than a small fraction of any insert's face area. Further the tool's cutting edge "rides up" on the face for the adjacent inserts' outer circumference faces so that any given tooth cannot engage beyond a shallow depth. This tool does not jamb, kick back or dig too deeply : all of those characteristics seem potentially problems with the blade you're showing?
To increase this very slow and shallow cutting/gouging tool's rate of material removal I remove one of the three blades.
And finally, this tool's guard (above) has a couple of very narrow steel 'spur's' (or tangs ?) added to #1 narrow the blade circumference segment that can reach material for excavation; #2 to allow balance by the operator both behind and in front of the cutting blade (stack) so that while narrow areas can be easily accessed with good control and visibility the tool can 'rock' back and forth to allow variable access in boat work; and #3 the UHMW tape on the lower support tang allows the tool to slide on a surface littered with aluminum chips- something that is very hard to achieve with a steel base you show in your post?
Summary, I think this tool has some uses for Hull Seams at the outside of the chine, butt seams outside and for other locations like the gunwale where access for the large base is unfettered - for those who weld inside first and back chip outside- this tool should provide good open area access. But I'm still troubled by the blade design. I think the tool shown may have great usefulness on sheet goods on horses, during prep in some seams but... I hope I've shown why I think the design has some potential problems for the welded aluminum boat builder?
(However) A video of the tool in use on an inside corner fillet, or a fillet recess gouge prep, or even a seam prep step on sheet goods still on the layout table would help me to understand the tool's target market better than I can from the photos posted. Chip loading, depth of cut, access, visibility are all matters that I see as (MY) concerns; all because I've built various versions of this type of tool for 40some years and have made countless mistakes in the various details I've listed.
Alphaprotools, I'm looking forward to seeing a video, or the uTube link to an existing video so i can watch the tool in use. Thanks for posting.
DISCLAIMER: I realize my "meat axe"/Widow Maker/ mis use of a grinder is likely unmarketable as a UL tested tool! I simply present this image and description as an educational reference
about the various features that I've found needed
(by me) in these types of tools within my experience
. AAB.com and Forum and its sponsors, contributors, and management in no way advocates the mis-use of power tools by anyone! My design, construction, use, and display of this tooling combination is solely my own idea and is shown ONLY to further the discussion
about using electrical power tools in the welding preparation process for plate aluminum boat building.